Boiler plug



Sept. 11, 1928. 1,683,726

( E. K. PIERCE BOILER PLUG Filed Dec. 30, 1926 v Patented Sept. 7 11 1928.

- 1,683,726 PATENT OFFICE.

ELWOOD K. PIERCE, 01 SPRINGFIELD, OHIO, .ASSIGNOR TO THE CAST STEEL DEVICES COMPANY, OF LIMA, OHIO, .A CORPORATION OF OHIO.

BOILER Imus.

Application filed December 30,1926 Serial No. 157,931.

This invention relates to removable closures for pressure chambers such as tube still junction boxes, headers, return bends, etc, and has for its principal obJect to provide a pressure resisting closure that can readily applied or. detached, and to permit ready access to the inside of the chamber.

The invention may best be understood by reference to the accompanying drawing, in which Figure lis a plan view of the device disposed in lockingposition. 0

Figure 2 is a sectional view taken on line 2-2 of Figure 1.

Figure 3 is a perspective view of the removable locking piece, showing details of the locking lugs thereon. Figure 4 is'an enlarged fragmentary view showing a portion of the retainingfianges 0 with which the locking lugs engage.

Referring now to details of the devlce 11-. lustrated herewith, 10 indicates a pressure chamber casing to which the device is applied with annular opening 11 forming a seat for the closure and a cylindricalwall or ring 12 surrounding the outer slde of said seat and preferably formed integral with the casing 10. Y

The closure device comprises a plug member 13 having an annular inwardly inclined face 11 adapted to engage the seat 11 as shown. This plug member is provided with spaced holes 14, 14 in its upper face, adapted to receive a grinding tool of any approved t pe for grinding said plug in'its valve seat, t ereb 'aflt'ording a tight pressure reslstlng joint or the purpose intended. The plug is maintained in place by means of a 'set screw 15, having a threaded engagement 40 with a removable locking piece 16 which is detachably connected by means of lugs withdrawn from the orifice. In order to accommodate the sto a recess 21 is formed at a corner of the loc ing lug 17 in position .the position in which it is inserted in or to permit the locking piece to be dropped 7 in the orifice without interference with the stop 20. This recessed portion 21 is clearly shown in Figure 3.

After the locking lug is in position as shown in F igure 1, the set screw is brought into contact with the pedestal 22 on the top of valve member 13 and by screwing down the set screw 15 the plug 13 maybe tightened in its seat, forming a tight 'oint.

Among the advantages oi the device above described is the provision for easy removal or replacementof the plug, and means for regrinding the plug when necessary in order to assure a pressure-tight joint at all times. A further advantage is aiforded by providing the locking lugs 17, 17 and their cooperating flanges 19, 19 of maximum width, so as to be rotatable through a full 90 angle, and providing correspondingly broad bearing surfaces, so as to eliminate dan er of tipping or accidental displacement oi? the locking piece.

I claim as my invention:

1. In a device of the character set forth an annular casing provided with a pair of oppositely disposed locking flanges and intermediate slot openings all of substantially equal circumferential length, a closure member, a locking piece, a screw threaded throu h said locking member for engaging said 0 osure member, said locking piece having a pair of oppositely disposed lugs adapted to be inserted in said slot openings and rotatable into interlocking position beneath said locking flanges, and a stop formed integrally with said casing at one side of one of said slot openings limiting rotation of said locking member at substantially a quarter turn from its unlocked position, one of said locking lugs being cut away at a lower corner thereof to accommodate said stop. I

2. In a device of the character described, a chamber having an opening defined by a frusto-com'cal plug seat, a plug adapted to fit in said seat to form a pressure-tight joint,

5 an annular casing above. saidopening. provided with a pair of oppositely disposed locking flanges and intermediate slot openings, a locking piece adapted to be inserted in said slot openings and rotatable into 10 interlocking position beneath said locking 

